Fuel injection nozzle



Dec. 23, 1958 v. D. ROOSA FUEL INJECTION NOZZLE Filed April 13, 1956 INVENTOR. VERNON 0. 9008A BY $427M ATT RNEYS ww QM QS Q m 9 injection pressure.

United States Patent G F UEL INJECTIQN NOZZLE Vernon D. Roosa, West Hartford, Conn.

Application April 1a, 1956, Serial No. 578,010

12 Claims. (Ci. 29-107.6)

This invention relates to fuel injection nozzles for internal combustion engines, and more particularly to such nozzles of the type having an inwardly opening plunger valve whichis adapted to be lifted from its seat by the pressure of fuel supplied to the nozzle.

In the operation of fuel injection nozzles of the inwardly opening plunger valve type, one of the difliculties heretofore experienced has arisen from the fact that a close sliding fit is required between the plunger and the nozzle body to minimize leakage and prevent excessive loss of This close sliding fit, however, renders the mating surfaces of the valve plunger and nozzle body susceptible to sticking and binding during nozzle operation, particularly where there is any warping of the parts during assembly of the nozzle or under the high temperature conditions of engine operation. Such sticking has a highly undesirable effect on such factors as injection timing, fuel spray pattern, fuel-air ratio, and the like, and hence can seriously affect engine operation.

Accordingly, one object of the invention is to provide an improved nozzle of the inwardly opening plunger valve type in which the valve plunger is mounted in a novel manner permitting close tolerances while reducing the possibility of seizure or binding of the nozzle valve.

Another object is to provide such a nozzle wherein the valve plunger is mounted for movement relative to the nozzle body in such manner as to provide an improved fiow path for the fuel and so as to provide simple and easy adjustment of the operating characteristics of the valve.

Another object is to provide a nozzle of the character described which is simplified in construction and reduced in cost, which may be easily assembled and regulated, and in which alignment of the valve and associated parts is automatically achieved during assembly of the nozzle.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the'scope of the application of which will be indicated in the claims.

In the drawing:

The single figure is a longitudinal sectional view of a nozzle constructed in accordance with the invention.

Referring to the drawing, the exemplary nozzle shown therein and embodying the present invention includes a two-part body having a front body member 2 and a rear body member 4. The rear body member 4 has an enlarged center section 6 and a rearwardly extending projection 8 of diminished diameter. The body member 4 has three bores hereinafter referred to as the front bore 10, rear bore 12 and side bore 14. The front bore 18 and side bore 14 communicate at the intersection denoted at 16, while the front bore 18 and rear bore 12 are interconnected by an opening 18 in wall 20. The side bore 14 is threaded as indicated at 22 and provides the inlet for the high pressure fuel which is to be ejected through the nozzle.

The front body member 2 is threadably received in the front bore 10 and a gasket 24 is provided between the shoulder 26 and the body member 4 to assist in maintaining the two parts in fluid tight relationship. The front body member 2 has an axial throughbore 28 which is flared at the forward end as indicated at 30 and which is enlarged at its rear end as indicated at 32.

The nozzle valve is in the form of an elongated plunger or rod 34 having a conical forward end 36 which is adapted to cooperate with a conical seat 38 in a centrally apertured orifice plate or tip 40 at the forward end of the nozzle. In accordance with the invention the valve plunger 34 is dimensioned relative to the diameter of bore 28 so as to form a clearance space therewith eliminating the conventional lap fit between the stem and nozzle body and also providing a passageway for the fuel to the forward end of thenozzle. The rearward portion of plunger 34 is slidably supported in a guide or sleeve 42 situated in bore 10 and having an enlarged parti-spherical head 44 which swivelly engages a complementary forwardly facing concave surface 46 concentrically formed on the wall 20 of the rear body member at the entrance to the opening 18. The sleeve or guide 42 is retained in seated position against surface 46 but permitted swiveling movement by a compression spring 49 acting between the underside of head 44 and the front body member 2. The parti-spherical surface of head 44 and surface 46 are preferably lap fitted to minimize fuel leakage into the opening 18 despite any pivoting or swiveling movement of sleeve 42 relative to the body member 4. Similarly, the mating surfaces of plunger 34 and sleeve 42 are lap fitted to minimize leakage.

Further in accordance with the invention, the forward end of the valve plunger 34 is slidably supported in a bearing in the form of a laterally adjustable centrally apertured plate 48 sandwiched between the nozzle tip 40 and the front end of front body member 2. The tip and plate 48 are clamped in position by a cup-shaped cap nut 50 threaded onto front body member 2 and having an internal conical surface 52 which co-operates with a bevel 54 on the front of the tip so as to insure automatic centering of the tip relative to the nozzle body. The nut 50 is dimensioned to form a clearance with plate 48 facilitating free lateral adjustment of the plate relative to tip 40 prior to clamping. Fuel flow through the plate 48 is permitted by passages 56 connected at their rearward ends to bore 28 and communicating with passages 58 in the front face of the plate which may be shaped and arranged in any desired manner in accordance with the fuel spray characteristics desired. To prevent fuel leakage around plate 48 the abutting surfaces of the plate, tip and forward end of the front body member are provided with a lap fit.

With this arrangement, when the nozzle is assembled the valve and associated parts are automatically correctly aligned because the tip 40 is centered by the conical surface 52 of cap nut 50 and automatically centers the forward end of valve 34. The forward end of the valve 34 automatically positions plate 48 so that its central opening is disposed in properly centered relation with respect to valve seat 38, and the sleeve 42 will swivel on surface 46 as necessary to line up with the valve stem axis. When the nut 50 is tightened it clamps the plate 48 and tip 40 in this correctly established position, and plate 48 thereafter serves to maintain the valve 34 in properly centered relation with valve seat 38 both when the valve is closed and when the valve is lifted to permit fuel discharge from the nozzle. Since the sleeve 42 effectively serves as an adjustable bearing capable of pivoting .on surface 46 to accommodate lateral adjustment of plate 48 as well as any shifting of the valve stem axis which may occur during or after assembly of the nozzle, any

orifice of tip 40 takes place. injection, the fluid pressure on the valve 34 is reduced possibility of'sticking of the valve or valve stem during nozzle operation is thus effectively overcome.

The rearward .end of the valve 34 is received in a s p'ring'seat' 64 biasedforwardly by a closing spring 66 heldby an adjustable retainer 68 threaded into re'ar bore 12. The retainer has a central bore 70 which threadably receives a pin 72 providing an adjustable lift stop for the valve 34. With this arrangement, the nozzle valve opening pressure may be adjusted as desired by merely turnthe rearward end of the projection 8. A leak-off connection (not shown) may be attached to projection 8 to draw "off any fuel which may succeed in escaping from the rear of the nozzle.

When the nozzle has been assembled and placed in operation, fuel'under pressure is introduced through inlet "14 and passes relatively freely through opening 16,

around the guide 42 and spring 49, and thence along the "passageway provided between valve 34 and bore 28 to the passages 56 and 58 of guide plate 48. The fuel pres- .sure thus applied to the tapered tip 36 of valve 34 thrusts the valve rearwardly against the bias of spring 66 to the extent permitted by stop 72 and ejection through the Upon completion of the and the spring 66 returns the valve to closed position.

By reason of the support of the plunger 34 only at its extreme ends by guides which are automatically aligned :when the nozzle is assembled, the possibility of sticking or binding of the plunger is greatly reduced and at the same time adequate protection against leakage and loss of pressure is provided. In addition, the elimination of provides a simplified fuel flow arrangement without the need for auxiliary bores, etc. in the nozzle body. Further, the nozzle is simple to assemble and adjust and will operate effectively over long periods of time without undue wear or failure.

"a lap fit between the plunger and the main nozzle body As many changes could be made in the above con- I 'struction and many apparently widely different embodiments of this invention could be made without departing from the scope hereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a fuel injection device, a nozzle body having a valve chamber, a valve plunger of smaller cross section than said chamber disposed in the chamber, and means adjustably supporting the plunger for reciprocating move- -ment longitudinally of the chamber comprising a first guide in which the plunger is axially slidable disposed adjacent one end of the chamber and movable laterally of the chamber, a second guide movable relative to the first guide disposed adjacent the other end of the chamber, saidplunger being axially slidable in said second guide for movement relative thereto, and a seat for mounting and centering said second guide relative to the axis of the chamber.

2. In a fuel injection device, a nozzle body having a valve chamber, a valve plunger of smaller cross section than said chamber disposed in the chamber, and means adjustablysupporting the plunger for reciprocating movement longitudinally of the chamber comprising a first guide in which the plunger is axially slidable disposed adjacent one end ofthe chamber and movable laterally of the chamber rneansfor fixing said first guide in adjusted ilateraljposition, .a'second ,guidemovable relative to the firs t guide, said plungerx being axially slidablein the isecond guide for movement relative thereto, and aseat at the other end of the'chamber mounting said second guide for adjustment into registry with'the first-guide but preventing longitudinal movement thereof with the plunger.

3. In a fuel injection device, a nozzle body having a valve chamber, a valve plunger of smaller cross section than said chamber disposed in the chamber, and means adjustably supporting the plunger for reciprocating movement longitudinally of the chamber comprising a first guide disposed adjacent one end of the chamber and movable laterally of the chamber, and a second guide disposed adjacent the other end of the chamber mounted for tilting movement relative to the axis of the chamber, said plunger extending through apertures in both the first and second guides and being axially slidable therein.

4. In a fuel injection device, a nozzle body having a cylindrical bore, a cylindrical valve plunger of smaller diameter than said bore disposed in the bore, and means adjustably supporting the plunger for reciprocating movement longitudinally of the bore comprising an apertured plate through which the plunger extends at one end of the bore and adjustable laterally of the bore, and a sleeve through which the plunger extends adjacent the other end of the bore mounted for tilting movement relative to the axis of the bore, the plunger being axially slidable in both the plate and the sleeve.

5. In a fuel injection device, a nozzle body having an outwardly opening bore forming a valve chamber, an elongated valve plunger of smaller diameter than said bore disposed in the valve chamber, a first guide for the plunger comprising an apertured plate and means supporting the plate at the opening of the bore in laterally adjusted position, and a second guide for the plunger comprising a sleeve having a parti-spherical head, and a seat complementary to said head at the inner end of the bore.

6. In a fuel injection device, a nozzle body having an outwardly opening valve chamber, a valve in said chamber comprising an elongated plunger of smaller diameter than the chamber having a tapered outer end, a nozzle tip having a seat for said tapered outer end, a first guide for the plunger comprising an apertured plate, means for securing the nozzle tip and first guide to the nozzle body at the opening of the valve chamber and permitting lateral adjustment of the first guide, and a second guide for the plunger comprising a sleeve having a partispherical head, and a seat complementary to said head at the inner end of the bore.

7. In a fuel injection device, a nozzle body having an outwardly opening bore forming a valve chamber, an elongated valve of smaller diameter than said bore disposed in the valve chamber and having a tapered outer end, a nozzle tip having a seat for said tapered outer end, a cap for securing the nozzle tip at the entrance to the bore, a first valve guide comprising an apertured plate of smaller diameter than the cap disposed between the nozzle tip and nozzle body, and a second valve guide comprisinga sleeve having a parti-spherical head, and a seat complementary to said head at the inner end of the valve chamber.

8. In a fuel injection device, a nozzle body having an outwardly opening bore forming a valve chamber, a valve in said chamber comprising an elongated plunger of smaller diameter than the chamber, a nozzle tip having a seat for the outer end of the valve, means for securing the nozzle tip to the nozzle body at the bore opening, an apertured guide plate for thevalve between the nozzle tip and nozzle body adjustable laterally of the bore, a guide sleeve for the valve having a parti-spherical head, a seat complementary to said head at the inner end of the valve chamber, spring means urging the sleeve into said seat, and means for admitting fuel under pressure to the bore intermediate the guide plate and guide sleeve.-

9. In a fuel injection device, a nozzle body having a valve chamber, an orifice member at the outer end of the valve chamber having a valve seat, a valve within the valve chamber and axially movable with respect thereto and dimensioned to form a clearance space between the valve and said nozzle body, a first valve support having an opening slidably accommodating said valve and dimensioned for lateral adjustment relative said body to permit centering of said opening relative to said valve seat, means for securing said first support in adjusted position relative to said valve seat, an internal concave bearing surface in said body facing said first support a second support in said body axially removed from said first support and having a bore within which said valve is slidably supported and a parti-spherical surface concentric with said bore and seated in said concave bearing surface of said body, and means biasing said second support against said internal spherical surface, whereby movement of said valve during lateral adjustment of said first support is accommodated by pivoting of said second support on said internal bearing surface.

10. In a fuel injection nozzle, a body having an outwardly opening bore, an orifice plate at the open end of the bore having a central aperture formed with a valve seat, a support plate disposed between said orifice plate and said body and having a central opening forming a bearing, said support plate being laterally slidably adjustable relative to said orifice plate to permit positioning of said opening in concentric relation with said valve seat, means for clamping said orifice plate and support plate to said body in mutually concentric relation, an

internal bearing surface in the body concentric with the axis of the bore, a sleeve within the body having a throughbore and a concentric parti-spherical surface complementary to said internal bearing surface, a spring holding said sleeve against said internal bearing surface, and a valve engageable with said seat dimensioned to form a clearance space with said body and slidably supported in said support plate and in said sleeve.

11. In a fuel injection device, a nozzle body having a bore forming a valve chamber, a nozzle tip having a discharge orifice and a tapered valve seat, means to clamp the nozzle tip at the entrance to said bore, a valve plunger of smaller diameter than the bore and disposed therein having a tapered end adapted to seat in the tapered valve seat of the nozzle tip, a front guide for the plunger comprising an orificed disc situated between the tip and nozzle body and adjustable radially thereof, a rear guide for the plunger comprising a sleeve having a rearwardly facing parti-spherical head, and a seat complementary to said head at the inner end of the bore, a spring retaining the sleeve in said last-named seat but permitting swivelling movement thereof, means biasing the plunger toward the tapered valve seat, means limiting rearward movement of the plunger, and means for admitting fuel under pressure to the passageway between the plunger and said bore.

12. In a nozzle, a body having a bore, a plate covering the front end of said bore and having a central opening forming a bearing, an orifice member in front of said plate having a valve seat, a cap clamping said orifice member and plate to said body and dimensioned to permit lateral adjustment of said plate for centering of the opening therein relative to said valve seat, an annular shoulder in said bore having a concentric forwardly facing concave surface, a sleeve having a parti-spherical surface at one end complementary to and engaged with the concave surface on said shoulder, a spring for holding said sleeve against said shoulder, a valve in said body engageable with said valve seat and having a stern slidably supported exclusively in said bearing and in said sleeve, valve closing means including a spring retainer in the form of a bushing threadably adjustable in said bore and a compression spring acting between said retainer and a spring seat on the rearward end of said valve stem, a pin threadably adjustable in said bushing providing a stop limiting rearward movement of said valve stem.

References Cited in the file of this patent UNITED STATES PATENTS 2,154,875 Streby Apr. 18, 1939 2,214,757 Alden Sept. 17, 1940 FOREIGN PATENTS 489,509 Germany Jan. 17, 1930 555,433 Germany Feb. 2, 1933 1,032,162 France u... Mar. 24, 1953 

